The present invention relates to an arrangement to dampen the oscillating motion of a bolster in a railway truck side frame. More particularly, the invention relates to a winged friction shoe and complementary bolster wherein a winged surface and an additional flanged surface on the friction shoe engage a complementary sloped surface and a raised flange on the bolster.
The present arrangement is an improvement over the friction shoe arrangements shown in U.S. Pat. Nos. 2,953,995 and 4,109,585, both of which are assigned to the assignee of the present invention.
The type of railway car truck to which the present invention relates comprises two spaced side frame members each having an opening arranged to resiliently support opposite ends of a bolster. A spring biased friction shoe is provided which includes a substantially vertical wall engageable with a friction surface on the side frame. The friction shoe also includes flanges or wings together with two additional flanged surfaces which project laterally from a body portion of the shoe. These wings and additional flanges bear against a complementary sloped surface and a raised flange on the bolster.
The provision of additional bearing surfaces by the additional flange of the friction shoe contacting the side of the raised flange of the bolster acts to spread the friction forces over a greater contact area between the friction shoe and the bolster. Accordingly, the service life of the friction shoe and the truck bolster are extended.
Further, the additional flanges will tend to center the friction shoe in the side frame opening, thereby reducing the undesirable contact at the sides and, accordingly, increase the stability of the friction shoe.
It is an object of the present invention to provide an arrangement for dampening the oscillating motion of a bolster in a railway truck side frame.
It is a further object of the present invention to provide an arrangement for dampening the oscillating motion of a bolster in a railway truck side frame by the use of a friction shoe which contacts the bolster and the side frame and wherein an extended service life of the friction shoe and the contacting surfaces of the side frame and bolster are provided.